1. Field of the Invention
The subject invention is generally related to a coaxial cable testing device of modular construction which is capable of both checking cable electrical continuity and detecting unauthorized or "bandit" splitters, and more particularly, for a coaxial cable testing device of modular construction which is configured in one arrangement for checking cable electrical continuity and is reconfigured to another arrangement for detecting bandit splitters.
2. Description of the Prior Art
In recent years, many households have begun subscribing to pay cable television (CATV) as a source of viewing entertainment. Pay television channel signals are generally supplied via coaxial cable transmission lines to the subscriber's home. Cables are routinely checked for electrical continuity during the installation process and in trouble shooting an installed system. Subscription rates are based on the type of service, i.e., number and kind (movie, commercial broadcast, special interest, etc.) of channels, and the number of television receivers connected to the cable system. Cable television suppliers need security for their cable lines; therefore, a need exists for cable television suppliers to detect unauthorized interception of cable television signals. Unauthorized interception usually occurs when a bandit splitter has been illegally installed to allow a cable to one site to service two or more sites or service two or more receivers at the same site. Currently, bandit splitters are detected by technicians examining the site locations while on service calls; however, clever hiding of a bandit splitter generally will allow avoiding detection.
U.S. Pat. No. 4,074,187 to Miller et al discloses a cable tester for multi-pair shielded cables which is capable of detecting the continuity of a pair of wires in the cable and shorts between pairs of wires or a wire and a grounding shield within the cable. A first module is connected to the pairs of wires at one end of the cable and a second module is connected to the pairs of wires at the other end. The first module includes a battery, a termination, and a plurality of light emitting diodes (LEDs). Circuitry is arranged such that a technician is given a visual indication when faults are present in the cable. The second module includes a termination and LEDs. The LEDs in the second module aid in the determination of pairs of wires within the cable and indicate the polarity of a pair of wires. The invention is used primarily for trouble shooting cash register systems in large department stores and is not applicable to testing coaxial cable. Moreover, in order to conduct all the tests it is necessary that the cable be connected at both ends to the two modules.
U.S. Pat. No. 4,293,376 to Bartol discloses a probe for sensing characteristics of electrical devices utilizing a magnetic switch sensor. The probe allows a technician to quickly determine if a relay or solenoid has been energized. When the probe is placed within a magnetic field, the reeds of a reed switch close to complete a circuit. Current from a storage battery within the probe may then flow through a lamp to give a visual indication of the solenoid's status. The probe is a small unit which can easily be carried by a technician.
U.S. Pat. No. 4,366,434 to Ellis discloses a combined voltage detector and electrical continuity checker which has a pencil like configuration. The testing device includes an insulation piercing needle, three LEDs, and two socket connections for connecting a flexible insulated cable that has an alligator clip at on end. Depending on the test to be performed, the flexible cable is placed in a particular socket and the needle is used to pierce the insulation to a conductor in a cable while the alligator clip is connected to ground. The LEDs provide a visual indication of the results of the testing.
None of the patents in the prior art disclose a cable testing device which allows a technician to check for cable continuity in a coaxial cable and to detect bandit splitters. None of the patents in the prior art show a cable testing device of modular construction wherein a technician can configure the several pieces in different arrangements for performing different tests.